One such gas-insulated busbar component is known, for example, from DE 101 19 530 A1. A switchgear assembly which is disclosed there is designed for a three-phase power supply system and has two busbars which are routed parallel to one another and are each composed of busbar components whose end faces are connected to one another by means of a gas-tight flange connection. Each busbar component has busbar conductors, which are encapsulated in a three-pole form in a housing, and is filled with an insulating protective gas with a high dielectric strength. The housing, which is at ground potential, is connected in a gas-tight manner via a tubular connecting stub to a switch housing, in which circuit breakers are arranged. Switch disconnectors with protective gas insulation are accommodated in the connecting stub and in each case connect one busbar conductor to one of the circuit breakers in a contact position. Outdoor bushings which are attached to the switch housing are used for connection of the circuit breaker to air-insulated high-voltage lines, with each high-voltage line being connected to the switch disconnector via one of the circuit breakers. The busbar conductors with protective gas insulation in the already known busbar component can thus be electrically connected to the air-insulated lines only via a circuit breaker.
Further busbar components, which have a plurality of encapsulated poles and a single encapsulated pole, are known, by way of example, from DE 31 37 783 and DE 31 41 437 A1.
One object of the invention is to provide a gas-insulated busbar component of the type mentioned initially, which can be connected in a simple manner to an air-insulated conductor, and can be disconnected from it, even in the operating state.
The invention achieves this object in that the switch disconnector is arranged in an outdoor bushing which is attached to the housing.
One or more air-insulated lines can be moved into a protective gas atmosphere, which is contained in the interior of the housing when the busbar component is in the operating state, in a simple manner via the outdoor bushing. In this case, the busbar component is connected in a gas-tight manner to further tubular housings via expedient connecting means such as flange connections, thus resulting in a closed gas area which can be filled with a protective gas such as sulfur hexafluoride.
When the switch disconnector is moved from a contact position, in which current can flow via the switch disconnector, to a disconnected position, in which the current flow is interrupted, an air-insulated line can be disconnected in a simple manner from the busbar conductor associated with it. According to the invention, this thus allows direct movement of a busbar from air insulation into gas insulation. According to the invention, there is no need for any further components or switches. The change in the insulation medium is advantageous, for example, in the case of so-called hybrid switchgear assemblies.
In the preferred exemplary embodiment according to the invention, three busbar conductors are provided, each having an outdoor bushing, with the distances between the outdoor bushings corresponding to the voltage-dependent flashover distance in order to prevent voltage flashovers. A busbar component according to the invention which has been developed further in this way is particularly suitable for three-phase power supply systems.
According to one expedient further development in this context, the outdoor bushings are arranged on a plane. This allows the outdoor bushings to be aligned vertically, with their center of gravity arranged precisely above the housing to which they are fitted, thus simplifying the design of the busbar component.
The outdoor bushings are expediently tubular or hollow-cylindrical. In the case of busbar conductors with a plurality of encapsulated poles, these conductors normally extend parallel to one another in a horizontal direction. Particularly in a situation such as this, it is advantageous for the outdoor bushings to be aligned vertically and for their center of gravity to be located precisely above the busbar, thus improving the stability of the gas-insulated busbar.
In one preferred embodiment of the invention, at least one of the outdoor bushings has a grounding switch. The grounding switch has a grounded switching finger which, in a grounding position, rests on a mating contact which is electrically connected to the busbar conductor. A grounding shaft is expediently provided in order to drive the grounding switch, and is mounted in attachment means in the outdoor bushing. In this case, the grounding shaft is, for example, driven by motor or by hand.
Each switch disconnector is advantageously held in the outdoor bushing by holding means composed of dielectric material. The holding means ensure that the switch disconnector is held in the outdoor bushing independently of the busbar conductor. This allows the outdoor bushing to be produced as an independent component together with the switch disconnector and to be connected in situ to the housing and to the busbar conductor, for example via an expedient plug-in contact. The plug-in contact or any other connection between the switch disconnector and the busbar conductor provide additional retention for the switch disconnector, and increase the stability of the switch disconnector.
The holding means are advantageously gas-tight. By way of example, a bulkhead bushing may be used as a gas-tight holding means, and bounds a disconnector gas area that is formed in the outdoor bushing. In this case, a connecting conductor which is electrically connected to the switch disconnector passes through the center of the bulkhead bushing, and is connected in a gas-tight manner to the bulkhead bushing via expedient sealing means. The disconnector gas area thus forms a gas area which is independent of the busbar area that is bounded by the housing, and can be filled, for example, with a different gas or can have a different pressure applied to it.
In contrast to this, the holding means are gas-permeable, so that a common gas area is formed by the interior of the outdoor bushing and its housing interior in the operating state and can be checked for leaks after final installation of the gas-insulated busbar component into an expedient installation, by means of a joint leak test. By way of example, a post insulator is suitable for use as the gas-permeable holding means.
The switch disconnector advantageously has contact pieces whose end faces are opposite one another, in which case the switch disconnector can be moved by the initiation of a linear movement from a contact position, which allows current to flow, to a disconnected position, in which an electrically isolating gap is formed between the contact pieces. According to this expedient further development of the invention, the design of the switch disconnector is very largely matched to a homogeneous cylindrical conductor which extends in an axial direction, so that it is possible to make use of experiences with conventional outdoor bushings which do not have any switch disconnectors in their interior. This applies both to their design and to the material that is used.
The switch disconnector expediently has a fixed-position female contact as well as a sliding contact which is firmly supported on attachment means of the outdoor bushing via a hollow connecting rod, with a switching pin whose movement is guided by the sliding contact being provided in order to make contact with the female contact, and the female contact is driven via drive means which are arranged in the connecting conductor. The drive means which are arranged in the hollow connecting conductor, for example coupling rods, pivoting levers or the like, are encapsulated by this conductor, thus avoiding voltage peaks at edges and corners of the drive means, and thus partial discharges, even during a drive movement. Furthermore, the switch disconnector has two stationary contact pieces, which can be held in a simple manner. This avoids a complex moving bearing for a contact piece on the attachment means.
In a further expedient refinement of the invention, at least one disconnector shaft is provided for introduction of a drive movement to the switch disconnector. In this case, each disconnector shaft is mounted by means of an expedient rotating bearing in attachment means in the outdoor bushing, with expedient sealing means ensuring gas-tight bushing of the disconnector shaft, for example through the outer wall of the attachment means of the outdoor bushing. The disconnector shaft can, of course, also be mounted in a gas-tight manner in the housing. The drive movement according to this embodiment of the invention can be introduced via a rotary movement into the interior of the outdoor bushing, which is gas-insulated during operation.
According to one expedient further development, an isolating rocker, which is composed of a dielectric material, is provided for introduction of a drive movement. The isolating rocker is mechanically connected, for example, to a coupling rod which forms a switching pin at its end remote from the isolating rocker, which switching pin produces the conductive connection between the contact pieces in the switch disconnector when the latter is in a contact position. The isolating rocker converts a rotary movement as a drive movement to a linear movement, and introduces a translational movement into the switch disconnector, which is designed in a corresponding manner to a push switch.
Each outdoor bushing is advantageously equipped with a current transformer. The secondary of the current transformer is connected to the grounded housing and may be in the form of a current adaptor so that there is no need to open the common or the separate gas areas when it becomes necessary to replace the current adapter.
Field control elements are expediently provided in order to avoid partial discharges in the outdoor bushing.
Furthermore, a display element may be advantageous in order to indicate the position of the switch disconnector.
At least one drive unit, which is supported on the outdoor bushing, is advantageously provided in order to produce a drive movement. This allows the outdoor bushing to be produced as a ready-to-use individual component, independently of the housing. A drive unit can drive either the switch disconnector of one pole, or else the switch disconnectors of all of the poles.